1. Field of the Invention
The present invention relates to an apparatus and a method of filling a desired amount of a microscopic toner powder for developing an electrostatic latent image into a second container without excess or deficiency from a first container.
2. Discussion of the Background
Conventionally, a powder toner for developing an electrostatic latent image is often filled from a first container into other second containers. For example, Japanese Laid-Open Patent Publication No. 9-193902 discloses a method of filling a toner powder into a toner receiving container from a toner feeding container equipped with an auger inside for stirring the toner and a rotary valve at the bottom. The method includes a process of increasing fluidity of the toner by feeding air into the toner stirred in the toner feeding container and a process of feeding the toner into the toner receiving container through a feeding tube and compressing the toner to fill the toner therein in the high density, wherein an exhaust tube for circulation located between the toner feeding container and the feeding tube separates the air from the toner and circulates the air including the toner into the toner feeding container.
A toner for developing an electrostatic latent image is a powder having an extremely small particle diameter and has less fluidity than other powders such as ceramic materials in spite of having a lower specific gravity than such other powders, and has a relatively high agglutinability. Recently, smaller particle diameters are required to comply with demands for a high-resolution image, and a lower-temperature melting resin is required to comply with demands for saving energy and an instant high-speed fixation. However, use of such particles results in problems of agglomeration, adherence to and filming of the toner over a surface of the other materials. Accordingly, in order to improve these properties and avoid the fluidity deterioration and agglomeration, in many cases, ultra-fine particles such as a fluidity improver, an agglomeration inhibitor and a charge controlling agent to improve chargeability of the toner are applied to a surface of the toner. Therefore, in terms of preventing these ultra-fine particles from separating and releasing from the toner and maintaining the chargeability, fluidity and agglomeration resistance thereof, it is not desirable that the toner is stirred or fed by means of an auger or a screw conveyor giving an excessive stress thereto.
Particularly, a color toner has a small particle diameter, and includes a charge controlling agent, a fluidizer, an agglomeration inhibitor and a fusion inhibitor on a surface thereof. Therefore, the color toner has poor fluidity because the particles intertangle each other, and it is not desirable to use a conventional mechanical apparatus such as a rotary valve and an auger since a strong external force applied to the toner involves the risk of impairing the properties thereof.
When a toner and air are mixed to make the toner pneumatic, a toner cloud (a nebula toner formed from a mixture of a toner and air) having floating ultra-microscopic toner is formed and a volume of the toner increases. It is difficult to quickly separate air from the toner cloud only by a structure and a location of a separation tube, and therefore it is difficult to control a compressed amount of the toner by an air separation from the toner cloud using such a tube. When air is supplied to the extremely microscopic toner, a flowing phase thereof increases quickly and easily changes to a dust phase, and it takes time to collect the toner from the dust phase and the dust contaminates the circumference. Once a toner cloud is formed, it takes up to several hours for the toner to fall onto the bottom by itself. It is not easy to fluidize the accumulated toner and fill it into a second container while moderately feeding air to prevent formation of a large toner cloud.
In addition, when the toner is distributed from a first storage container into many second containers, the toner in the second containers occasionally has an irregular ingredient due to the air fed into the storage container.
Because of these reasons, a need exists for an apparatus and a method of fluidizing a toner stored in a first container, and quickly and precisely distributing the toner into a small container without impairing the toner properties and composition and contaminating the circumference, which is easily automated and has good manageability.